Connector and receptacle containing a physical security feature

ABSTRACT

A connector system that provides discriminating mating between plugs and receptacles by using a system of geometrically matched connector components which allow certain pairs of connectors to mate but which prevent all other combinations of connectors to mate.  
     In a preferred embodiment, the connector system comprises (a) a plurality of receptacles, each receptacle having an inner surface with a first geometry; (b) a plurality of plugs, each plug having a second geometry; (c) wherein the second geometry of a plug cooperates with at least one first geometry of a receptacle to allow the plug and the at least one receptacle to mate, while the second geometry of the plug physically interfering with all other second geometries of all of the other receptacles of the plurality of receptacles to prevent mating therewith.

FIELD OF THE INVENTION

[0001] The present invention relates to connectors for the use withfiber optics, and more specifically relates to a system of novelkey-slot structures to provide several mutually exclusive connectors fordiscriminating between users.

BACKGROUND OF THE INVENTION

[0002] Fiber optics have become increasing more popular in recent years.Fiber optic technology provides several advantages over the conventionalcopper wire-based technology. Fiber optics allow for large volumes ofdata to be transferred quickly over long distances. In addition, fiberoptic communications systems are not susceptible to electromagneticinterference (EMI) and provide substantially increased bandwidth.

[0003] With the increase in use of fiber optic systems, connectors havebecome necessary for making connection between separate fiber opticcables. Connecting various independent fiber optic cables can bechallenging as a result of the nature of fiber optics. It is importantthat the optical fibers being connected are properly aligned properlyaligned, in the axial and transverse directions, so that there isminimal loss of light resulting from the connection. It is essentialthat the connection be made in such a manner that no data is lost at thepoint at which the optical fibers are joined.

[0004] As the fiber optic field has grown, there has been much effortdevoted to developing various connectors to meet the needs of fiberoptic systems. Connectors such as the SC Type connector and ST typeconnector became widely used as the industry standard. These types ofconnectors attempt to provide accurate and precise connection betweenfiber optic cables.

[0005] While fiber optic systems first gained acceptance as the backboneof many network systems, copper wire technology was still the mostprevalent manner of connecting various workstations to the networksystem. Recently, however, the use of fiber optic technology has beenextended to the complete network system including workstations, oftenreferred to as fiber-to-the-desk (FTTD) applications.

[0006] The growth of FTTD applications complicates the requirements ofoptical connectors. Connectors were needed that were small enough to beused in an office environment and that could be easily installed in thefield. A group of connectors were developed which are known as SmallForm Factor (SFF) connectors. SFF connectors are designed to be thefiber optic replacement for the small connectors used in copper wiretechnology, such as, for example, RJ-45 connectors. These small,efficient, easy to use SFF connectors have become a new industrystandard and should contribute to the continued growth of FTTDapplications. One SFF connector of particular interest herein is theMT-RJ connector. Details on the construction of this type of connectorcan be found in Manning ( U.S. Pat. No. 6,224,268).

[0007] The increased popularity of FTTD applications creates a newproblem as many large networks implement SFF connectors such as theMT-RJ connector. A need has developed to limit access to the networksupported by the fiber optic cables, for security or other reasons. Itis desired to limit access to certain networks to those who have theproper authorization to access the information. Also, in areas whereseveral networks exist, it is desired to control the user group whichhas access to any particular network. While some access limitation canbe obtained through the use of software (e.g., passwords), furtherlimitation can be obtained by using some type of physical limitationdevice.

[0008] Therefore, what is desired is a means to physically regulateusers of a network by allowing access to the desired users andpreventing access to all others.

SUMMARY OF THE INVENTION

[0009] The present invention provides for a connector system thatprovides discriminating mating between plugs and receptacles by using asystem of geometrically matched connector components which allow certainpairs of connectors to mate but which prevent all other combinations ofconnectors to mate.

[0010] In a preferred embodiment, the connector system comprises (a) aplurality of receptacles, each receptacle having an inner surface with afirst geometry; (b) a plurality of plugs, each plug having a secondgeometry; (c) wherein the second geometry of a plug cooperates with atleast one first geometry of a receptacle to allow the plug and the atleast one receptacle to mate, while the second geometry of the plugphysically interfering with all other second geometries of all of theother receptacles of the plurality of receptacles to prevent matingtherewith.

[0011] Preferably, the receptacle is a jack having a tub and the firstgeometry comprises a key and a plurality of ribs extending inward, andthe plug comprises a housing and a ferrule contained within the housing,wherein the second geometry comprises a slot in the housing forcooperating with the key and secondary slots for cooperating with theribs, and wherein the slot and the secondary slots cooperate with thekey and the ribs to effect pre-alignment of the ferrule before finalmating of the ferrule.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIG. 1 depicts a top view of a plug as it is insert into theinside portion of the jack, which is known as the tub portion of thejack., for connector intended to mate.

[0013]FIG. 2 depicts an expanded top view of the end of the key shownprior to an attempt to mate the connector plug with the tub of aconnector jack for a connector not intended to mate.

[0014]FIG. 3 depicts an end view of the plug component, showing a slotwhich is used to allow or prevent mating with a particular tub.

[0015]FIG. 4 depicts an end view of the tub component, showing the keywhich is used to allow or prevent mating with a particular plug.

[0016]FIG. 5 depicts a plug with a slot configuration capable of matingwith a plurality of jacks (i.e., a master plug).

[0017]FIG. 6 and FIG. 7 shows the slot and key features as combined withan MT-RJ connector manufactured by Tyco Electronics (Harrisburg, Pa.).

DETAILED DESCRIPTION OF THE INVENTION

[0018] The present invention relates to a connector system comprising aseries of connector components which interconnect with each other in adiscretionary way. Referring to FIG. 1, a preferred embodiment of amating plug 101 and receptacle 100 of the connector system isillustrated. As shown, the plug 101 is partially inserted into thereceptacle 100, which, in this embodiment, is a jack having a tubportion 102. Although a jack is discussed herein in detail, it should beunderstood that the receptacle of the present invention is notrestricted to a jack and may be any structure configured to receive aplug, including, for example, an adapter for connecting two plugstogether or an integral connector on an active device (e.g.,transceiver) or passive device (e.g., splitter).

[0019] The plug typically contains a conductive element such a fiber orwire which mates with a similar element in the receptacle. In fiberoptic applications, it is common for the conductive element to becontained in a ferrule, which in turn is housed by the plug. In apreferred embodiment, the ferrule is an MT-type ferrule.

[0020] The outer surface of the plug 101 and the inner surface of thetub 102 have first and second geometries, respectively, which cooperateto allow only certain pairs of plugs and receptacles to mate (herein“mating pairs,” “mating plug and jack,” or “keyed pair”), and whichphysically interfere for all other combinations of plugs and jacks(herein “non-mating pairs,” “non-mating plugs and jacks” or non-keyedpairs), thereby preventing non-mating plugs and jacks from effecting anoptical or electrical coupling.

[0021] The first and second geometries may embody any known keyingmechanism which discriminates between connector components. Such keyingmechanisms include, for example, a key and slot relationship between theplug and jack, a receptacle dimensioned to receive only certain sized orshaped plugs, and even a magnetic signature for either attracting (formating pairs) and repulsing (non-mating pairs). Preferably, the keyingmechanism involves just a slight modification to the plug and jack suchthat essentially the same molds can be used to manufacture connectors ofdifferent keyed pairs. Although molding is preferred, it is should beunderstood that other techniques for producing the first and secondgeometries can be used including, for example, over molding andmachining.

[0022] In a preferred embodiment, the invention uses a key and slotmechanism. Specifically, the slot can be embodied in the first or secondgeometry and the key can be embodied in the other geometry. In theparticularly preferred embodiment shown in FIGS. 1-4, the key is part ofthe second geometry, while the slot is part of the first geometry; thatis, the plug 101 has a slot 103 and the tub portion 102 of the jack hasa key 104.

[0023] This configuration is preferred since the key may cooperate withother “ribs” on the connector for pre-alignment purposes. Morespecifically, with particular reference to FIG. 3, an end view ofhousing 301 of the plug 101 is shown. The housing comprises four wallseach wall having a slot 103, 302 a, 302 b, and 302 c, respectively. FIG.4 depicts an end view of housing 401 of the tub 400 in which the key 104and ribs 402 a, 402 b, and 402 c are disposed on the walls of thehousing. The key 104 and the ribs 402 a, 402 b, and 402 c cooperate withthe slots 103, 302, 302 a, 302 b, and 302 c, respectively, to effectpre-alignment of ferrule located within the plug with the jack beforefinal mating of the connector plug with the connector jack. The finalmating may be between the conductive elements of the connector system,such as, for example, between a couple of MT-type ferrules, which employprecise alignment pins/receiving holes on the ferrule face. Suchferrules are well known in the art. By pre-aligning the MT ferrulesthrough the synergistic use of the key and slot, the inter-engagement ofthe closely-toleranced alignment pins/receiving holes is facilitated.The above-described synergistic keying and aligning feature of thepresent invention is realized with the MT-RJ connector (TycoElectronics, Harrisburg, Pa.).

[0024] In a preferred embodiment, the mating end of the key 104 containsa flat portion shown as 105 and the mating end of the plug 101 has achamfers 106 on the corners of the edges of the slot 103, while theremainder of the mating end of the plug comprises a flat portion 107.The radius comers on the key 106 and the chamfers on the plug 107 workas a guiding device and provide for the necessary alignment between thekey and the slot when the plug is inserted into the tub of the jack. Onthe other hand, as shown in FIG. 2, when a user attempts to mate twonon-mating plug and jack components, the flat portion of the key 105contacts the flat portion of the plug 107 and provides for definitephysical interference between the plug and jack when slot and key do notcorrespond. Accordingly, the use of this geometry prevents a user fromforcing two non-mating plugs and jacks together. Therefore, the physicalinterference provided between the flat portion 105 of the tub and theflat portion 107 of the key assures that only desired combinations ofplugs and jacks will mate.

[0025] The position of the key 104 on the tub 102 and the slot 103 onthe plug 101 can be varied in such a manner so that a plurality ofmutually-exclusive slot and key positions are formed. In one embodiment,the series of key and slot locations are mutually exclusive so thatthere is a one-to-one correspondence between jacks and plugs. In anotherembodiment, certain plugs may be configured to mate with a variety ofdifferent jacks. For example, it may be worthwhile to give networkadministers or people with high security clearance certain “master”plugs which are capable of mating with a number of jacks havingdifferent slot positions. Referring to the figures, FIG. 5 shows anembodiment of a master plug 501 which has a slot 502 that is configured(which, in this embodiment, means it is wide enough) to mate with jacks503 and 504 which have different key positions 505 and 506,respectively. Although a wide slot is used in this embodiment to effectmating with two or more jacks having different key configurations, itshould be understood that other embodiments are possible, such as, forexample a plug with two or more slots.

[0026] The number of possible mutually exclusive mating pairs for agiven plug and receptacle is a function of the physical parameters ofthe plug and the receptacle. More specifically, with reference to FIGS.1-4, mutual exclusivity is assured by adhering to the followingrelationships:

X ₁ −C/2+(D−A)+Δ<=F/2  (1)

X ₂ −B/2</2−W  (2)

X _(1a+)Clear₁ +Z=X _(1b)  (3)

[0027] wherein:

[0028] A=the width of the plug 101;

[0029] B=the width of the slot 103 on the plug 101;

[0030] C=the width of the key 104;

[0031] D=the distance across the opening of the tub;

[0032] F=the width of the ferrule residing within the plug;

[0033] Δ=CL_(F)-CL_(A), wherein

[0034] CL_(A)=centerline of the width of the plug; and

[0035] CL_(F)=centerline of the ferrule residing within the plug.

[0036] X₁=the distance from the center of the opening in the tub 102 tothe center of the key 104 for each mutually exclusive position.

[0037] X₂=the distance from the center of the plug 101 to the center ofthe slot 103 for each mutually exclusive position;

[0038] X_(1a)=the X₁ distance for a sequentially first key in a seriesof connectors;

[0039] X_(1b)=the X₁ distance for a sequentially second key in a seriesof connectors;

[0040] W=the wall thickness of the plug housing

[0041] Z=the minimum distance required to ensure that the flat portionof the key does not contact the flat portion of the plug 107 when a userattempts to mate a mating pair;

[0042] Clear₁=the clearance distance between the center side of the keyand the center side of the slot;

[0043] These relationships must be satisfied for the mating pairs tomate and for the non-mating pairs to definitely not mate. Specifically,for a mating pair, Relationship (1) requires that half the ferrule widthmust be no less than X₁ less one half of C added to the differencebetween the width of the tub opening D less the width of the plug addedto the difference between the centerline of the ferrule within the plugand the centerline of the plug. This assures that the key is notpositioned outside of the area on which at least a portion of theferrule will reside. By adhering to this parameter, the key will havesome overlap with the ferrule, and thus will provide for pre-alignmentof the ferrule in the same manner as do the ribs on the three sides ofthe ferrule without the key.

[0044] Relationship (2) requires that X₂ added to one-half of dimensionB is less than one-half of dimension A less W. This assures that theslot resides on the plug within the confines of the plug walls.

[0045] Finally, according to Relationship (3), for each mutuallyexclusive position, the distance X₁ for the first connector in thesystem (X_(1a)) added to Clear₁ added to a predefined interferenceinterval Z would correspond to the distance X₁ for the next slot/keyposition (X_(1b)) Z is the minimum distance required to ensure that theflat portion of the key does not contact the flat portion of the plug107 when a user attempts to mate the two portions of a connecter whichis intended to mate.

[0046] By way of example, four mutually exclusive locations for locatingthe slot on the plug housing and the key on the tub are defined belowfor an MT-RJ connector. The MT-RJ connector has the followingdimensions:

[0047] A=7.15±0.05 mm

[0048] B=1.25 mm

[0049] C=0.95±0.04 mm

[0050] D=7.24±0.04 mm

[0051] F=4.5±0.04 mm

[0052] Clear₁=0.15 mm

[0053] W=0.8 mm

[0054] Based on these MT-RJ dimensions, it has been found that thefollowing X₁ key positions satisfy the relationships above: Mating pairKey Position X₁ 1 1 0.8 mm 2 2 1.6 mm 3 3 −0.8 mm 4 4 −1.6 mm

[0055] Although the data above indicates four mutually exclusivepositions, it should be understood that additional positions arepossible within the parameters of the MT-RJ connector. Additionally, itshould be understood that the combinations of various key positions canbe used to increase the number of permutations of mating pairs. Forexample, in addition to the four mating pairs listed above, additionalmating pair configurations may obtained from the following combinationsof key positions: Mating pair Key Positions 5 1, 2 6 1, 2, 3 7 1, 2, 3,4 8 2, 3 9 2, 4 10 2, 3, 4 11 3, 4 12 1, 3 13 1, 4 14 1, 3, 4 15 1, 2, 4

[0056] In a preferred embodiment, the key and slot components arecombined with the industry standard MT-RJ connector. FIG. 6 and FIG. 7show the key-slot combination added to the MT-RJ connector as producedby Tyco Electronics of Harrisburg, Pa.

[0057] FIGS. 6 (a)-(c) show the plug 602 of the MT-RJ connector combinedwith the slot 601 of the present invention. FIGS. 7(a) and 7(b) show thecenter tub portion 703 of an MT-RJ connector jack. The key is shown as701 located in one of the plurality of possible positions. The threepre-alignment ribs are shown as 702 a, 702 b, and 702 c. The key 701functions as the discriminating member for allowing or preventing matingwith a plurality of plugs, while at the same time functioning as thepre-alignment member for the remaining side of the ferrule not alignedwith ribs 702 a, 702 b, and 702 c.

[0058] To provide a simple and readily apparent indication to the userof which plugs mate with which receptacles, it is preferable to markmating pairs with indicia or color to indicate their compatibility. In apreferred embodiment, the components of a mating pair are a similarcolor different from all others used in the connector system.

[0059] The system described allows for a series of mutually-exclusiveconnectors to be used in a manner which provides physical security to anetwork system. In light of the often highly sensitive data stored onmany of the networks in use today, this is a highly desirable feature.The present invention is an effective way to segregate separate networksand assure that the proper users are connecting to the desired network.Additionally, the present invention may be employed in the manufactureof devices in which fibers or wires need to be connected in particulararrangements. More specifically, the discriminating connectors of thepresent invention can be engineered into a system such that, duringmanufacturing, the correct connection of the fibers/wires is ensured bythe mating pairs and their ability to prevent all other “incorrect”connections. Applications requiring particular routing of fibers orwires include, for example, routers, backplane assemblies, and evencomponent devices such as multiplexers/demultiplexers.

[0060] It should be understood that the foregoing is illustrative andnot limiting and that obvious modifications may be made by those skilledin the art without departing from the spirit of the invention.Accordingly, the specification is intended to cover such alternatives,modifications, and equivalence as may be included within the spirit andscope of the invention as defined in the following claims.

What is claimed is:
 1. A connector system for providing discriminatingmating between plugs and receptacles, said system comprising; aplurality of receptacles, each receptacle having an inner surface with afirst geometry; a plurality of plugs, each plug having a secondgeometry; wherein the second geometry of a plug cooperates with at leastone first geometry of a receptacle to allow said plug and said at leastone receptacle to mate, said second geometry of said plug physicallyinterfering with all other second geometries of all of the otherreceptacles of said plurality of receptacles to prevent matingtherewith.
 2. The connector system as set forth in claim 1, whereineither the said first geometry or said second geometry comprises atleast a key, and the other comprises at least a slot.
 3. The connectorsystem as set forth in claim 2, wherein said receptacle is a jack havinga tub, said tub comprising said key and a plurality of ribs extendinginward, said plug comprising a housing and a ferrule contained withinthe housing, said housing comprising said slot for cooperating with saidkey and secondary slots for cooperating with said ribs, said slot andsaid secondary slots cooperating with said key and said ribs to effectpre-alignment of said ferrule before final mating of said ferrule. 4.The connector system as set forth in claim 2, wherein the key has a flatportion on the mating end and each plug has a flat portion on the matingend.
 5. The connector system as set forth in claim 4, wherein the plugcomprises at least a housing with a housing center and a ferrule havinga width, a housing wall thickness, a slot, and a flat portion, andwherein said jack comprises at least a key with a width and a center anda flat portion, wherein the position of the slot is defined accordingthe following formula: X ₁-C/2+(D-A)+Δ<=F/2 wherein: A=the width of theplug C=the width of the key; D=the distance across the opening of thetub; F=the width of the ferrule residing within the plug;Δ=CL_(F)-CL_(A), wherein CL_(A)=centerline of the width of the plug; andCL_(F)=centerline of the ferrule residing within the plug. X₁=thedistance from the center of the opening in the tub to the center of thekey for each mutually exclusive position; and wherein the position ofthe key is defined according the following formula: X ₂ +B/2<A/2-W wherein: X₂=the distance from the center of the plug 101 to the centerof the slot 103 for each mutually exclusive position; W=the wallthickness of the plug housing; B=the width of the slot on the plug; andwherein mutual exclusivity of the slot and molded key positions areassured according to the following formula: X _(1a)+Clear₁ +Z=X _(1b) wherein, X_(1a)=the X₁ distance for a sequentially first key in aseries of connectors; X_(1b)=the X₁ distance for a sequentially secondkey in a series of connectors; Z=the predetermined distance required toassure that the said flat portion of the key will not contact said flatportion of the plug; Clear₁=the clearance distance between the centerside of the key and the center side of the slot;
 6. The connector systemas set forth in claim 2 whereby the connector type is push-pullconnectors.
 7. The connector system as set forth in claim 6 whereby theconnector type is an MT type connector.
 8. The connector system as setforth in claim 7 whereby the connector type is an MT-RJ connector. 9.The system as set forth in claim 1, wherein each corresponding plug andreceptacle is marked for visual identification, wherein said particularvisual indicia is at least one of color, alphanumerical, symbol, orother visually distinguishable mark.
 10. A system of plugs for use inconjunction with a system of corresponding receptacles comprising; aplurality of plugs, each plug having a distinct geometry, to allow eachplug to be mated with only one of a system of corresponding receptacles,said geometry causing a physical interference to prevent each plug frommating with all other receptacles.
 11. A system as set forth in claim10, wherein the said distinct geometry is a flat portion and a slotresiding within said flat portion.
 12. A system as set forth in claim10, wherein each plug is marked for visual identification, wherein saidmarking is at least one of color, alphanumerical, symbol, or othervisually distinguishable mark.
 13. A system of receptacles for use inconjunction with a system of corresponding plugs comprising; a pluralityof receptacles, each receptacle having a distinct geometry, saidgeometry to allow each receptacle to be mated with only one of a systemof corresponding plugs, said geometry causing a physical interference toprevent each receptacle from mating with all other plugs.
 14. The systemas set forth in claim 13, wherein the said distinct geometry is a moldedkey located on the center tub.
 15. The system as set forth in claim 14,wherein the said molded key has a flat portion located on the mating endof the molded key.
 16. A system as set forth in claim 15, wherein eachplug is marked for visual identification, wherein said marking is atleast one of color, alphanumerical, syr mbol, or other visuallydistinguishable mark.